The Z-Way Android app is good, but what would make it really good is if you add support for Widgets, for placing devices directly on the desktop. And if you add support for Tasker, so that it registers as a Tasker plugin. Being able to generate Tasker profiles based on Z-Way device status and events, as well as easily getting and setting device status in Tasker both on and off the home wifi, would be fantastic.

(Oh, and please add an on/off button of some sort to the multilevel switches in the UI.)

I actually have something halfway similar to what you're describing, only it's through Tasker (because I'm also automating the api calls) and I'm using the ZAutomation api, which in my current setup only works locally. Changing to your approach looks like it will work outside of the home wifi as well, but does it support getting values as well as setting them?